A variety of technologies are available for creating interactive web pages. Web pages often include scripts that imbue a web page with functionality beyond that available with hypertext markup language alone. In addition, features/functionalities are added to a web browser with web browser add-ons. Add-ons include themes, extensions, and plug-ins. These allow the appearance of a web browser window to be customized. Extensions typically integrate with logic of a web browser to add functionality to the web browser. Plug-ins also add functionality to a web browser, but remains separate from the web browser. A plug-in and a web browser communicate via an established interface, through which values and/or code are communicated. Further, web browsers aggregate additional technologies (e.g., extensible markup language, cascading style sheets, document object models) with scripts and add-ons for a highly interactive web page.